1. Field of the Invention
The invention pertains to an apparatus and method for assembling a stretchable cover upon a rigidly backed foam cushion.
2. Description of the Related Art
Cushioned and covered components are used in a, variety of products such as automobiles, furniture and building components wherein a plush, soft, attractive surface is desired. In such instances, it is common to use a relatively rigid backing of wood or paperboard in combination with an expanded foam affixed to the backing whereby the foam cushion will maintain a predetermined shape and configuration.
When covering a backed foam cushion with a flexible cover, such as made of fabric, vinyl, leather or the like, it is necessary that the cover be dimensionally fabricated accurately so as to closely fit and encase the backed cushion to minimize the occurrence of wrinkles and unsightly ribs or waves in the cover. Obtaining a wrinkle-free covering of a backed cushion is difficult in that the cover must closely and firmly encase the backed cushion, and because of the close tolerances, difficulty is encountered in assembling the backed foam cushion and cover.
Known apparatus for assembling backed foam cushions and covers have not been readily adaptable to high production assembly techniques, and considerable hand work is often required to make the cover acceptably fit and enclose the backed foam cushion. Such hand work is slow and expensive, and if care is not taken to properly position the cover on the backed foam cushion, wrinkles and ridges will appear which aesthetically detract from the finished product.
It is an object of the invention to provide a method and apparatus for assembling a rigidly backed foam cushion and a stretchable cover wherein the cover may be quickly and accurately placed upon the backed foam cushion in a tight fitting and wrinkle-free manner.
Yet another object of the invention is to provide a method and apparatus for assembling backed foam cushions and stretchable covers wherein backed foam cushion assemblies of irregular lateral configuration can be quickly and accurately covered with a stretchable cover, and wherein the cover is stretched in accord with the configuration of the backed cushion assembly.
Yet a further object of the invention is to provide a method and apparatus for assembling a rigidly backed foam cushion and stretchable cover wherein the degree of stretching of the cover that occurs during assembly can be varied in a predetermined manner by cams and cam followers, and in accord with the lateral configuration of the backed cushion.
In the practice of the invention, it is the purpose to assemble a rigidly backed foam cushion with a stretchable cover wherein, even though the lateral dimension of the cushion configuration may be variable, the stretching of the cover during assembly can be controlled to provide an optimum fit between the cover and backed foam cushion to eliminate wrinkles and ridges.
The apparatus of the invention is preferably vertically oriented having an upper ram portion and an assembly portion located below the ram portion.
A pair of carriages are mounted on the frame assembly portion in side-by-side relationship movable upon elongated guides or ways whereby the carriages may move toward or away from each other in a lateral direction. Each of the carriages supports a pair of spaced plate-like stanchions which are mounted at their lower end upon the associated carriage and extend upwardly toward the frame ram portion. Two stanchions are mounted upon each carriage and the upper ends of the stanchions are unsupported whereby the stanchions are cantilever supported in a vertical position. The stanchions mounted upon a common carriage are spaced from each other by a dimension slightly greater than the thickness of the backing and foam cushion assembly, and the stanchions of the two carriages are in lateral alignment whereby the four stanchions together define a xe2x80x9cslotxe2x80x9d of a thickness slightly greater than the backed cushion assembly.
Each of the carriages includes a roller cam follower received within a cam slot formed in a cam plate mounted on the frame upon vertically disposed guides whereby the cam plate is capable of moving toward and away from the frame assembly portion.
In the preferred arrangement, the cam plate is connected to the ram such that the cam plate will move with the ram toward and away from the frame assembly portion. As the cam slots in the cam plate will be of a configuration usually complementary to the lateral configuration of the backed cushion assembly, the engagement of the carriage cam followers in the cam plate cam slots will cause the carriages to move laterally as the ram is lowered toward the carriages and frame assembly portion.
To further customize the stretching of the cover as the backed foam cushion is inserted therein, the outer edges of the stanchions, i.e. those stanchion edges laterally facing away from each other and the center of the frame and which engage the cover, may also be configured in accord with the shape of the foam cushion and cover to facilitate entry of the cushion into the cover and assure fitting of the cover to the cushion to produce a wrinkle-free product.
The cover is turned inside out and placed over the top of the stanchions and as the cushion is pushed into the pocket defined by the cover by the ram, the cover folds inwardly over the top of the stanchions while being stretched laterally by the stanchions. Accordingly, the cover is automatically removed from the stanchions as it is stretched thereby and as the cushion assembly is received within the cover. At the end of the ram stroke, the cushion assembly will be completely encased within the cover, the cover will have now been removed from the stanchions, and the assembly between the cushion and its cover is now complete, and the cushion/cover assembly will be located between the carriage stanchions.
The ram is now retracted away from the frame assembly portion. This movement causes an ejector head located between the stanchions to move upwardly with the ram as it retracts. The ejector head will engage the assembled cushion and cover and remove the same from between the stanchions as the ram retracts. This permits the operator to remove the assembled cushion and cover from the machine once the ram is fully retracted. Thereupon, a new cover may be inserted upon the stanchions and a backed foam cushion mounted upon the ram, and the assembly cycle repeated.
The practice of the invention permits a backed foam cushion to be quickly and accurately encased within a stretchable cover in a wrinkle-free manner, and even though the cushion may have a variable lateral dimension, the automatic control of the stretching of the cover by the movable stanchions, whose position is determined by the cam followers and cam slots, permits an improved assembly procedure than that previously obtainable, and permits a higher quality finished product to be achieved.